*{
	margin: 0;
	padding: 0;
}
.container{
	height: 100vh;
	width: 100vw;
	background-color: #2c3a47;
	display: flex;
	justify-content: center;
	align-items: center;
	z-index: 1;/* 这里为其加上z-index是为了防止伪元素下降到最低层，所有元素的最底层 ，在ul上面加也可以*/
	position: relative;
}
.container ul{
	display: flex;
	justify-content: center;
	align-items: center;
}
.container ul li{
	list-style: none;
	margin: 0 18px;
}
a{
	width: 64px;
	height: 64px;
	line-height: 66px;
	display: block;
	color: white;
	position: relative;
	text-align: center;
	font-size: 36px;
	border-radius: 50%;
	background: #2c3a47;
}
a:hover{
	text-shadow: 0 0 10px #00C9FF;
}
li a::before{
	content: "";
	position: absolute;
	top: 0;
	left: 0;
	border-radius: 50%;
	width: 100%;
	height: 100%;
	background-color: #2196F3;
	z-index: -1;
	transition: .4s;
	transform: scale(0.6);
}
li a:hover::before{
	box-shadow: 0 0 10px 2px #00C9FF;
	transform: scale(1.05);
}
.svg-icon{
	transition: 0.6s;
	  filter: invert(1);
}